Hooray: Philip Cowley's revolts.co.uk is back in action. Cowley studies parliamentary voting and in the past his website has been the definitive guide to Commons revolts. The site went into hibernation when his funding dried up but now he and his team are crunching the numbers again. For anyone interested in the way parliament works, that's good news.

Cowley has also just published his annual guide to rebellions in the last session of parliament. Lazy commentators complain about MPs now being spineless and compliant, but Cowley has shown conclusively that government backbenchers rebel more than their predecessors and the latest figures prove that today's MPs really are (to resurrect the old Carry On joke) revolting – more than any others since 1945.

The fourth session of this parliament (and Gordon Brown's second complete session as prime minister) saw Labour MPs defy their whips on 74 occasions. In raw terms, this was a drop on the 103 of the previous session, although still enough to constitute the fourth most rebellious session faced by New Labour's whips, and the ninth most rebellious since 1945.This raw figure, though, is slightly misleading, as there was a noticeable drop in the number of divisions taking place, from 341 in 2007-08, to 248 in 2008-09. Measured as a percentage of divisions, the 74 revolts equate to a rebellion in 30% of divisions, exactly the same as the preceding session's figure. Each of the four sessions of the 2005 parliament, therefore, has now seen a rebellion rate of between 20 and 30%, and the parliament as a whole is currently averaging a rate of 27%, on course to become the most rebellious in the postwar era. Even if the parliament's final session sees relative calm – as final sessions usually do – we still expect the 2005 parliament easily to break the postwar record, set by the 2001-05 parliament, of a rebellion in 20.8% of divisions. In absolute terms, that record has already been achieved; the 2005 parliament has already seen more revolts against the whip by members of the governing party than any other postwar parliament.

There's lots of other data in the handbook, which runs to 49 pages and covers every Labour Commons rebellion in 2008-09. It also tells you exactly how many times each backbencher has rebelled. This list is topped by John McDonnell, who defied the whips 46 times during the year.